1. Technical Field
This invention relates generally to static gaskets for use in sealing a clamped joint, such as that of an intake manifold of an internal combustion V engine.
2. Related Art
Clamped joints often do not have precise, uniform mating surfaces. As such, creating a gas and/or fluid tight seal across the joint can prove challenging. For example, the joint between an intake manifold and mating cylinder heads of an internal combustion engine, and particularly a V-type engine block, can be difficult to seal. The intake manifold is fastened to upwardly facing sealing surfaces of the cylinder heads with an intake manifold gasket or gaskets installed between the respective sealing surfaces of the cylinder heads and the manifold. When the fasteners properly tightened, the intake manifold and cylinder heads are clamped together, wherein the intake manifold gaskets serve to perfect a gas and fluid-tight seal at the joint. However, difficulties can arise when the sealing surfaces of the cylinder heads are misaligned. Misalignment can occur as a result of machining imperfections and/or stack-up tolerances from the various parts being fastened together, thereby bringing the sealing surface of one or both of the cylinder heads out of the predetermined ideal position to establish a tight seal. For example, an ideal position may call for the sealing surfaces of the cylinder heads to lie in a common plane. Stack-up tolerances may result in one or more of the sealing surfaces being positioned slightly above, below or skewed relative to the plane. The intake manifold, in turn, having a planar sealing surface requires the sealing surfaces of the cylinder heads to be coplanar to provide the proper support to the gaskets to achieve a gas and fluid-tight seal. When the mating sealing surfaces are misaligned relative to one another, a step is created in the otherwise planar support surfaces that abut the intake manifold gasket leading to irregular loading of the gasket and potential difficulties in achieving an adequate seal.
The problem is made worse by variation in the sealing conditions that can occur in the manufacture of engines. The stack-up tolerances may result in the sealing surfaces of one engine being in the proper planar arrangement, while the next engine may have one of the sealing surfaces stepped up from the plane and the next engine may have the same or the other sealing surface stepped down from the plane, and so forth. This changing environment presents a real challenge to static seal gaskets that rely on planar support surfaces for establishing a reliable seal.